This invention relates to hot water heaters, and more particularly to a method of removing sediment buildups therefrom and apparatus for carrying out the method.
Although the invention may be adapted for use to advantage in any hot water heater or boiler, it is primarily intended for use in conventional domestic hot water heaters, whether electric, gas-fired, or oil-burning. In most if not all models of such hot water heaters, a drain valve is provided on the sidewall of the tank, near the bottom of the tank. The invention makes use of that drain location for access to the tank to remove accumulated sediment.
In any hot water heater, sediment precipitates out of the water and tends to accumulate at the bottom of the tank. The composition of the sediment, and the degree to which it is a problem, obviously depends on the quality of the water supply.
Even where the water supply is relatively free from the minerals which make up most of the sediment, over time the sediment inevitably accumulates. Opening the drain plug periodically will serve to remove a small amount of sediment, principally that which is still in suspension near the bottom of the tank, or that which is freshly accumulated and has not had time to cake onto the bottom of the tank. However, merely opening the drain periodically only removes a very small amount of sediment, and will not result in any removal of the sediment which has caked onto the bottom of the tank.
Sediment in the bottom of the tank greatly reduces the life of a hot water heater. The primary failure mode for a domestic hot water heater is leakage, and an accumulation of sediment at the bottom of the tank is thought to be a primary cause of leaks.
The sediment shortens the water heater life, but also has adverse affects even while the hot water heater remains in service. In the case of a gas or oil-fired hot water heater, sediment at the bottom of the tank greatly reduces the efficiency, by interfering with the transfer of heat to the water. In the case of an electric hot-water heater, where the elements are immersed in the water, efficiency may not be reduced, but the overall volume of the tank may be significantly reduced, thereby affecting overall performance.
In practice, most hot water heaters are replaced when there is an excessive buildup of sediment. The home owner may not even realize that the reason for poor performance of the heater is sediment.
There is therefore a definite need, hitherto apparently unfulfilled, for some means of removing the sediment to prolong water heater life.